module fulladder4 (A,B,Cin,S,Cout);

	input [3:0] A,B;
	input Cin;
	output [3:0] S;
	output Cout;
	wire n1,n2,n3;

	fulladder1 U0 (.A(A[0]),.B(B[0]),.Cin(Cin),.S(S[0]),.Cout(n1));
	fulladder1 U1 (.A(A[1]),.B(B[1]),.Cin(n1),.S(S[1]),.Cout(n2));
	fulladder1 U2 (.A(A[2]),.B(B[2]),.Cin(n2),.S(S[2]),.Cout(n3));
	fulladder1 U3 (.A(A[3]),.B(B[3]),.Cin(n3),.S(S[3]),.Cout(Cout));

endmodule
